The Undoing Project: A Friendship That Changed Our Minds

“Freud was in the air but Danny didn’t want anyone lying on his couch, and he really didn’t want to lie upon anyone else’s.”

Lewis emphasizes Danny’s aversion to working as a clinical psychologist. Danny’s fascination with psychology derived from this desire to better understand human nature as a whole, as opposed to closely analyzing a single individual.

“If you can’t observe what is happening in the mind, how can you even pretend to make a study of it?”

This quote refers to the dilemma that faced many psychologists in the 1950s. Despite a desire to hold psychology to high standards of scientific study, the human mind was still so elusive and incomprehensible that many gave up on the idea of studying the human mind altogether.

“Part of the problem was the wild diversity of the people who wanted to be psychologists—a rattle-bag of characters with motives that ranged from the urge to rationalize their own unhappiness, to a conviction that they had deep insights into human nature but lacked the literary power to write a decent novel, to a need for a market for their math skills after they’d been found inadequate by the physics department, to a simple desire to help people in pain.”

Danny’s ambivalence toward becoming a psychologist stemmed from his frustration with many in the field who seemed to lack the high standards of scientific inquiry that he followed himself. Given that Danny considered science a conversation, his reluctance to commit to psychology also came from the feeling that most psychologists worked without really listening to one another.

“Presented with two lines of equal length, the eye is tricked into seeing one as being longer than the other. Even after you prove to people, with a ruler, that the lines are identical, the illusion persists: They’ll insist that one line still looks longer than the other.”

This passage refers to the Muller-Lyer optical illusion, where the power of perception often overrules mathematical precision. In other words, the mind’s perception becomes stronger than fact. This optical illusion came to mind for Danny when he was tasked with assigning Israeli military personnel to the right positions. His awareness of his limited powers of perception led him to create a personality test for the Israeli military.

“He’d found out something about people who try to divine other people’s character: Remove their gut feelings, and their judgments improved. He’d been handed a narrow problem and discovered a broad truth.”

Danny’s deduction about the fallibility of human judgments, particularly when these judgments rely on hunches and gut feelings, was an early precursor for his eventual research with Amos. His curiosity was stoked years before his path crossed Amos’s.

“Amos was fond of saying that interesting things happened to people who could weave them into interesting stories.”

This anecdote is a telling representation of how Amos viewed the world and the people in it, and his ego on full display here. Amos undoubtedly saw himself as someone who could tell a story, and moreover as someone interesting.

“What all those who came to know Amos eventually realized was that the man had a preternatural gift for doing only precisely what he wanted to do.”

Amos was unconcerned with social niceties or other people’s perceptions of him. He would do what he wanted to, when he wanted to, other people’s feelings about it be damned.

“Occasionally Amos offended someone—of course he did. His darting pale blue eyes were enough to unsettle people who didn’t know him. Their constant motion gave them the impression he wasn’t listening to them, when the problem, often, was that he had listened too well.”

Amos Tversky lived life to the fullest. Every conversation he entered was intentional on his part, and every interaction was an opportunity to learn or to spark some new intellectual inquiry. Of course, he lived in his own world, one where offending other people was not something he lost sleep about.

“The trouble with philosophy, Amos thought, was that it didn’t play by the rules of science.”

As Amos, like Danny, tried to determine which professional field he would enter, he eliminated philosophy. He was a scientist at heart, which ultimately led him to his line of inquiry within psychology.

“After taking classes in child psychology and clinical psychology and social psychology, he concluded that the vast majority of his chosen field was safely ignorable.”

After choosing to become a psychologist, Amos needed to decide what kind of psychologist he would be. He found most of psychology’s mainstream avenues of little interest, which led him to research the psychological science of decision making.

“How does a person decide where to live, or whom to marry, or, for that matter, which jam to buy?”

After joining the psychology department at the prestigious University of Michigan, Amos was drawn to one of its key members, Clyde Coombs. Coombs was interested in decisions that fall into life’s gray areas, choices that require more complex mental processes than ones that don’t involve more or less money, or more or less pain. These questions, about where to live or whom to marry, were what piqued Coombs’s interest.

“When people make decisions, they are also making judgments about similarity, between some object in the real world and what they ideally want.”

This passage refers to the coffee versus tea versus hot chocolate inquiry. When people make judgments about similarity, their minds quickly compare what the two things have in common with each other and with the ideal that a person wants. People make decisions when they have a context for classification.

“Israel took its professors more seriously than America did. Israeli intellectuals were presumed to have some possible relevance to the survival of the Jewish state, and the intellectuals responded by at least pretending to be relevant.”

When Barbara and Amos moved to Israel, Barbara soon noticed how much more confrontational Israeli students were toward their professors when they disagreed with the curriculum. She also noticed how much more urgent and relevant the world of academia was in Israel, where what was taught in the university lecture hall could have real-world, practical applications. Israel depended on this practicality.

“I knew four people who were killed in the Six-Day War—and I’d only been there six months.”

This passage refers to Barbara’s perception of community in Israel. People were more connected, more tightly knit to each other. After the Six-Day War, she actually experienced loss. This was not the detached experience that many Americans had toward the Vietnam War, but the immediate reality that war and death were all around.

“It turned out that Danny never really had to decide what kind of psychologist he would be. He could be, and would be, many different kinds of psychologists.”

Danny was first and foremost an intellectual. By refusing to box himself into a corner from a professional and intellectual standpoint, he had the freedom to become a multifaceted psychologist.

“On the one hand, [Foundations of Measurement] was a wildly impressive display of pure thought; on the other, the whole enterprise had a tree-fell-in-the-woods quality to it. How important could the sound it made be, if no one was able to hear it?”

This passage refers to Amos’s obscure and arguably obsolete textbook, Foundations of Measurement. Lewis emphasizes that the work was an incredible feat in one sense; it was logically sound and clearly indicative of a brilliant mind at work. However, its premise was dubious at best, and it did not accurately reflect Amos’s intellectual capacity.

“Amos had a gift for avoiding what he called ‘overcomplicated people.’ But every now and then he ran into a person, usually a woman, whose complications genuinely interested him.”

For the most part, Amos picked and chose who he engaged with, and with whom he developed any semblance of a relationship. Amos did what he wanted to, and in so doing largely avoided people who might bring him stress or complication. Lewis notes two exceptions, however: Dahlia Ravikovitch, a classmate who later became one of Israel’s great poets, and Daniel Kahneman. Though Danny was complicated in many ways, Amos was fascinated by him, which in some ways served as the impetus for their collaboration and friendship.

“A human being who finds himself stuck at some boring meeting or cocktail party often finds it difficult to invent some excuse to flee. Amos’s rule, whenever he wanted to leave any gathering, was to just get up and leave.”

Again, Amos is portrayed as someone who did only as he pleased. Social niceties were a waste of time; they were rules that only slowed people down from what they really wanted to do. Amos lived with a sense of urgency, believing that time was a precious commodity that could not be wasted.

“To acknowledge uncertainty was to admit the possibility of error. The entire [medical] profession had arranged itself as if to confirm the wisdom of its decisions.”

This passage refers to Donald Redelmeier’s concern that most medical doctors did not acknowledge how much uncertainty there is in the medical field. This concern ultimately led to his interest in the science of decision making and his collaboration with Amos.

“The failure of decision makers to grapple with the inner workings of their own minds, and their desire to indulge their gut feelings, made it quite likely that the fate of entire societies may be sealed by a series of avoidable mistakes committed by their leaders.”

These are Danny’s thoughts, spoken during a talk he called “Cognitive Limitations and Public Decision Making.” He was gravely disturbed by the lack of systems involved in high-stakes decision making. This lack of self-awareness, especially among people in positions of authority, had the potential to start wars, yet gut feelings and best guesses still remained the most dominant form of decisions, even at the highest levels.

“It was seldom possible for Amos and Danny to recall where their ideas had come from. They both found it pointless to allocate credit, as their thoughts felt like some alchemical byproduct of their interaction.”

Danny and Amos worked so closely together that it was rarely possible to locate the source of an idea. When they published papers together, they alternated whose name appeared first. The collaboration created enormous momentum for both of their professional careers, and in a sense it would define their professional legacies.

“As with some other fertile pairs, the partnership had created strains on their other close relationships.”

When Miles Shore interviewed Danny and Amos to better understand how productive pairs worked and functioned, he discovered that their close relationship had in turn jeopardized others. Danny, for instance, revealed that his collaboration with Amos had strained his marriage.

“Amos disliked prizes. He thought that they exaggerated the differences between people, did more harm than good, and created more misery than joy, as for every winner there were many others who deserved to win, or felt they did.”

In 1984, after receiving a MacArthur “genius” grant, Amos complained about the award, angry that he alone was honored while Danny was left out. Amos received many other awards, most of which completely ignored Danny. He felt as if this individualized attention on him would deal a death blow to collaboration with Danny, which is exactly what happened.